Flexible drill collars



Aug. 30, 1955 R. w. GOBLE FLEXIBLE DRILL COLLARS 5 Sheets-Sheet l FiledJan. 25, 1952 .IH I/IN- INVENTOR.

a/N LMU LUW ATTO/CP/VEYJ Aug'. 30, 1955 R. w. GOBLE FLEXIBLE DRILLCOLLARS I5 Sheets-Sheet 2 Filed Jan; 23, 1952 Aug. 30, 1955 R. w. GoBLEFLEXIBLE DRILL COLLARS 5 Sheets-Sheet 3 Filed Jan. 25. 1952 y f i Mm M7% 6 A ww am zyf ii L h L i 5f/ www il -l H fw a ./LL LL MM w M Uniterates f atent Otice FLEXIBLE DRILL COLLARS Ralph W. Goble, Denver,Colo., nssignor, by mesne assignments, to Oilwell Drain Hole DrillingCompany, Long Beach, Calif., a corporation of California ApplicationJanuary 23, 1952, Serial No. 267,810

4 Claims. (Cl. Z55-28) This invention relates to new and usefulimprovements in exible drill collars and relates particularly to thefluid conductors extending through such collars.

In the drilling of drain holes which are small diameter bores drilledoutwardly from a main well bore, it has` been the practice to employexible'drill pipe sections -f pipe to the drill bit and is ordinarilyunder considerable pressure. Obviously, to provide for eilicientcirculation of the drilling fluid to the bit the iiuidconductor throughthe flexible pipe sections of the string must be capable of withstandingand holding such pressure.

It is one object of the present invention to provide an improvedflexible drill pipe section or collar having a ilexible uid conductormounted axially therein, whereby drilling tluid may be circulateddownwardly through the pipe section or collar regardless of the ilexureor bending thereof.

An important object is to provide a flexible iluid conductor within aexible drill pipe section, together with an improved means formaintaining the seal at the ends of the fluid conductor throughout allbending movement of the pipe section. i

Still another object is to provide an improved fluid conductor assemblywithin a flexible drill collar, which conductor is constructed of astandard high pressure hose having fittings at each end thereof withmeans incorporated in the iittings to efciently seal between the ends ofthe hose and the bore of the drill collar.

A still further object is to provide a fluid conductor assembly whereinthe end ttings on the ilexible conductor are capable of a slidingmovement with respect to the drill collar or pipe section in which theconductor is mounted, with means for maintaining the seal between theends of the fluid conductor and the drill collar throughout such slidingmovement.

The construction designed to carry out the invention will be hereinafterdescribed together with other features thereof.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

Figure l is a view partly in section and partly in elevation of adrilling apparatus having a flexible pipe section or drill collarconstructed in accordance with the invention connected therein,

Figure 2 is an elevation of the drilling apparatus showing the sameoperating to drill a drain hole or auxiliary bore,

Figure 3 is a view partly in section and partly in elevation andillustrating the mounting of the drilling iluid conductor within theexible pipe section or drill collar,

Figure 4 is a horizontal cross-sectional view taken on the line 4-4 ofFigure 3,

Figure 5 is an exploded View of one of the end fittings for the tluidconductor,

Figure 6 is a view of the snap retaining ring which preventsdisplacement of the hose from the drill collar,

Figure 7 is a view partly in section and partly in elevation and showingthe position of one of the end fittings of the fluid conductor when thedrill collar or pipe section is exed, and v Figure 8 is a view partly insection and partly in elevation of the tool which is employed foractuating the end fittings.

In the drawings the numeral 10 designates a well bore from whichinclined or offset drain holes or bores of reduced diameter 11 (Figure2) are to be drilled. The drilling apparatus for forming the drain holesor auxiliary bores 11 is illustrated in Figure l and includes awhipstock 12 having an inclined face 13. A spiked footpiece 14 isconnected by a tubular section 15 with the lower end of the whipstockand is adapted to engage the lower end of the main well bore 10; thelength of the connecting element 15 may vary to properly locate thewhipstock y,

12 at the desired elevation in the main well bore.

An elongate tubular guide 16 is connected by a coupling 17 with a collar18 at the upper end of the whipstock. The usual drill pipe 19 extendsdownwardly from the surface of the well and has a sub 2t) connecting thelower end thereof with one or more lexible drill collars or pipesections A. A drill bit 21 which is pref-v.

pipe is rotated, the ilexible drill collars A function to transmitrotation to the bit 21. Initially the sub 20 is connected by shear pins22 to the tubular guide 16 and when so connected the drill bit 21 is inthe position shown in Figure l. The parts are lowered into the well borein this position and when drilling is to occur the pins 22 are shearedand thereafter the drill bit 21 will be guided at an inclination by theinclined face 13 of the whipstock in the manner illustrated in Figure 2.After drilling is complete, the drill pipe is raised and because the bit21 has a larger diameter than the whipstock collar 13 the drill pipefunctions to retrieve said whipstock.

Each drill pipe section or collar A is constructed of a plurality ofinterconnected elements which will transmit rotation therebetween whilepermitting free ilexure or bending of the section or collar. Theparticular construction of the type of connection between the elementsof the collar A is subject to variation and so long as the collar iscapable of easy flexing the purposes of the invention will beaccomplished.

During the drilling operation it is necessary to conduct drilling liuidto the drill bit 21, and it is apparent that since each ilexible drillcollar or section A is formed of a plurality of interconnected jointedelements, the flexible collar is not capable of conducting pressureiiuid therethrough. For the purpose of conducting pressure fluiddownwardly through the jointed flexible section or collar a Huidconductor assembly as shown in Figure 3 is provided. The upper endelement 23 of the flexible collar A is formed with a reduced pin section24 for' connection with the sub 20. An axial bore 25 is formed withinthe element 23 and beneath said bore is a counterbore 216 whereby aninternal shoulder 27 is provided within the element 23. An end iittinggenerally indicated at F in Figure 3 is mounted within the bore 25 ofthe element 23 lgaaiersted Aug. 30, 1955 and is connected to one end ofa fluid conductor 28, which conductor may be a standard high pressurehose. The fitting F provides a seal between the end of the hose orconductor 2S and the wall of the upper element 23 of the flexible drillcollar A.

The hose 26 has a similar fitting F' at its lower end, which fitting isslidable within the bore 29 of the lowermost element 3l) of the flexibledrill collar. The element 30 has a counterbore 31 which forms aninternal shoulder 32 therein. At its extreme lower end the ele ment 31Bof the flexible drill collar is formed with a box 33 whereby connectionthrough a sub 34 may be made with the drill bit 21. The lower fitting F'provides a seal between the lower end of the hose 2S and the lowermostelement 3l) of the flexible drill collar, and thus when tluid iscirculated downwardly through the drill pipe 19 such fluid enters theupper end of the fitting F, flows through the hose 28 and through thefitting F' to the drill bit. As will be hereinafter described, thefittings F and F are slidable axially within the respective bores 2S and29 of the end elements 23 and 30 of the `flexible drill collar and suchsliding motion permits free flexing of the drill collar A without anyloss of the seal.

The fittings F and F are identical in construction and a description ofone will suffice. In Figure 5 an exploded view of the fitting F isillustrated, and such fitting cornprises a tubular mandrel 46 having anaxial bore 41 extending entirely therethrough. The upper end of themandrel is enlarged at 42 and externally threaded at 43 whereby a collar44 may be secured thereon. The upper end of the mandrel has a pair ofdiametrically opposed wrench notches dfi while the collar 44 has similarwrench notches 46 in its upper end. The external surface of the collarhas an annular groove 47 therein for receiving a sealing ring 4S whichis preferably of the O ring type. An annular enlargement 49 is formedintermediate the ends of the mandrel to provide an external shoulder Sand beneath said shoulder the mandrel is externally threaded at i,whereby an outer sleeve member 52 may have its upper end threaded ontothe mandrel. As clearly shown in Figure 5, the sleeve 52 has internalthreads 53 engageable with the threads 51, and obviously the upper end54 of the sleeve may be connected to the mandrel in abuttingrelationship to the shoulder 5l). Below the threads 53 the bore of thesleeve 52 is slightly enlarged as indicated at 55, and the lower portionof the bore is formed with annular grooves S6. The contour orcrosssection of the grooves is such that when the end of the flexiblehose 2S is pressed therein, displacement of said hose from the groovesby longitudinal movement is prevented.

When the sleeve 52 is connected to the threads 51, the portion a of themandrel below said threads projects downwardly through the bore of thesleeve 52. The extreme lower end of the mandrel is reduced as indicatedat 5'7, and above this reduced portion is a beveled shoulder 58.

In the assembly of the fitting the end of the hose 28 is inserted intothe sleeve S2 so as to be opposite the annular projections 56a formed bythe annular grooves 56. The end Lilla of the mandrel is then inserted;into the bore 23a of the hose and the reduced end 57 of said mandrelfacilitates such insertion; as the portion 40a of the mandrel enters thebore the flexible mandrel of the hose 23 is deformed into the annulargrooves 56 in the manner illustrated in Figure 3. As the mandrel threads5i engage the threads 53 of the sleeve a relative rotation of the partsscrews the sleeve upwardly into abutting relationship to the shoulder S0on the mandrel, and at this time the end of the hose is firmly clampedbetween the portion 46a of the mandrel and the mandrel 42.

Thereafter, the collar dd having the O ring 48 within its groove isconnected to the threads 43 of the mandrel to complete the assembly asshown in Figure 3. For the purpose of tightening the collar 44 upon themandrel, a-

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(ill

wrench 60 which is illustrated in Figure 8 is provided. This wrenchincludes an inner tubular member 61 having Wrench lugs 62 on its lowerend and these lugs are engageable with the wrench notches 4S in themandrel 42. An outer sleeve 63 having wrench lugs 64 is rotatable aboutthe member 6l and its lugs are arranged to engage the notches 46 of thecollar 44. The member 61 may have a handle 61a while the sleeve 63 isprovided with a handle 63a to facilitate operation of these parts. ltwill be evident that the lug 62 of the inner member may be engaged withthe notches 45 of the mandrel, while the lug 64 of the sleeve may beengaged with the notches d6 of the collar. Thereafter a relativerotation of the sleeve 63 with respect to the member 61 will tighten thecollar upon the mandrel.

After the fittings F and F have been assembled in the manner abovedescribed, the fitting F is inserted into the bore 25 of the upperelement 23 of the flexible drilling collar. The external diameter of thecollar 44 is such that the collar has a sliding fit within the bore 25,and'- inward displacement is limited by the shoulder 27 within element23. Outward displacement of the collar 44v from the bore is prevented bya snap ring 65 (Figure 6) which engages within a groove 66 provided inthe outer portion of the bore of the end element 23. The collar 44 ofthe lower fitting is inserted within the bore 29 of the lower element 36of the flexible drill collar, and its inner movement is limited by theinternal shoulder 32. Outward displacement of the tting F is preventedby one ot the snap rings 65 which is mounted in an annular groove 67provided for the purpose within the lower end element 3@ of the drillcollar.

With the parts assembled as shown in Figure 3, it will be evident thatthe ends of the hose 28 are firmly clamped to the fittings F and F and atight sealing of the ends of the hose with the mandrels of the fittingsis effected. The provisie-n or" the O rings 48 in the collars 44 or" thefittings effects a sliding seal between the collars and the bore of theflexible drill pipe section. It is thus apparent that as drilling iiuidis circulated downwardly from the drill pipe l@ into the iiexible pipesections A, said fiuid will flow downwardly through the high pressurehose 2S and be conducted to the drill bit therebelow. Upon a liexure orbending movement of the sections A, it is apparent that the collars 44of the fittings F and F' may slide within their respective bores tocompensate for the bending movement and still maintain the seal. lnFigure 7 the upper fitting F is illustrated as having slid or moveddownwardly Within its bore 25 upon a bending movement or iiexure of theiiexible pipe section A. The O ring d3 maintains the seal with the wallof the upper element 23 ot' the flexible pipe section A throughout allmovements of the collar within its bore. Each fitting is relativelysimple in construction and comprises a minimum number of parts which maybe readily disassembled in the event that replacement of the hose or Orings is necessary.

Although the invention has been described above in its preferred form,as having fittings F and F axially slidable within the elements 23 and3l), respectively, in some instances it may be desirable to secure thefittings F and F' to the elements 23 and 3i), respectively, by threadsor any other suitable means, so that the fittings are stationary in theflexible drill collar. When the iittings F and F are thus madestationary, the hose 28 must vbe sufficiently flexible to stretchaxially upon flexing ofthe drill collars A in a path such as shown inFigure 2.

Using such construction of the fittings F and F and.

attached hoseZS, the G rings d3 could be eliminated since the rigidconnection of fitting F to element 23 and fitting F' to element 3% wouldseal off any fluid and direct it through the hose 28,

The foregoing disclosure and description of the invenv tion isillustrative and explanatory thereof, and various changes in the size,shape and materials, as wellY as-in the details of the illustratedconstruction may be made, within the scope of the appended claims,without departing from the spirit of 'the invention.

Having described the invention, I claim:

1. A flexible drill pipe section including, a plurality of elements,means for connecting the elements to each other to permit limiteddetlection of each element relative to its adjacent elements, wherebythe drill pipe section may undergo a flexing movement, said connectingmeans also securing the elements to each other so that rotation may betransmitted through said elements, a flexible hose extending axiallythrough said section, a tting connected to each end of the hose andslidable within the end portion of the bore of the pipe section, andmeans providing a seal between each fitting and said bore of the pipesection.

2. The combination with a flexible drill collar of a exible conductorextending axially within said collar, a fitting at each end of theconductor having sliding and sealing contact with the bore of the drillcollar, and

means for limiting the sliding movement of each fitting with respect tosaid collar.

3. The combination with a flexible drill collar of a fluid conductorassembly comprising a ilexible hose extending axially within the bore ofsaid flexible drill collar,

a ltting at each end of said hose, said fitting comprising a mandrelhaving a portion thereof engageahle within the bore of the hose, anouter clamping sleeve encircling the hoseand clamping the same betweensaid sleeve and the mandrel, and a collar of a diameter larger than themandrel secured to its outer ,end and having a sealing ring mounted onits exterior surface, said last-named collar being slidably disposedwithin the bore of the exible drill collar and having its sealing ringin sealing engagement with said bore.

4. The sub-combination set forth in claim 3, wherein the sealing ring isan O ring.

References Cited in the lile of this patent UNITED STATES PATENTS487,893 Schimper et al, Dec. 13, 1892 1,314,601 McCaskey Sept. 2, 19192,198,016 Rogers et al. Apr. 23, 1940 2,296,161 Hall Sept. 15, 19422,344,277 Zublin Mar. 14, 1944 2,485,976 Main Oct. 25, 1949 2,515,366Zublin July 18, 1950 2,521,127 Price Sept. 5, 1950 2,551,536 Harvey May1, 1951

